This invention relates to a magnetic recording/reproducing apparatus in which a magnetic sheet is used as a recording medium, and more particularly to a magnetic recording/reproducing apparatus which includes a moving mechanism of a control plate accessible to the magnetic sheet in order to maintain a desired head contact between a magnetic head and the magnetic sheet.
An electronic picture camera recently proposed reads out a still picture by a photographing apparatus to convert it into a video signal, and the thus-obtained video signal is recorded in a magnetic sheet by a magnetic recording apparatus. Recorded in this magnetic sheet are video signals for one scene in one track or two tracks. When the magnetic sheet is loaded into a reproducing apparatus, the video signals are reproduced and can be observed as a visible image through an output apparatus such as a picture tube and a printer.
The afore-mentioned type of a magnetic recording/reproducing apparatus is disclosed in, for example, Japanese Utility Model Early Disclosure No. 57(1982)-210696. In this prior art a magnetic sheet pack containing a magnetic sheet rotatable therein is loaded inside a pack holder. After a door is closed the pack holder is placed in a loaded position within the apparatus. According to this operation, the magnetic sheet is fixed to a spindle driven by a motor, and simultaneously, a magnetic head is caused to be in contact with the magnetic sheet. When in recording or reproducing operation, the magnetic head undertakes the magnetic recording/reproducing while the magnetic sheet is being rotated at a high speed of, for example, 3,600 rpm.
Generally in order to obtain a preferable recording/reproducing operation, it is required that a desired contact state between the recording medium and the magnetic head be maintained. However, since said magnetic sheet is extremely thin, as soon as the magnetic head contacts the recordable surface, the magnetic sheet tends to come out of contact with the head, which makes it difficult to obtain a desired head contact. In view of the foregoing, a groove is formed in a portion opposite to the magnetic head, and a control plate accessing to the magnetic sheet from the other side of the magnetic head is used. When the magnetic sheet is rotated, an air stream is produced and acts thereon to obtain a desired head contact. However, the conditions for obtaining such a desired head contact are extremely strict, and an accuracy as high as several tens of microns is required in order to repeatedly correctly position the control plate.
Said control plate is accessed to the magnetic sheet through the respective openings of a pack holder and a magnetic sheet pack during a time when the magnetic sheet is being rotated. On the other hand, the control plate must not be inside the pack holder during a time when the magnetic sheet pack is being loaded or unloaded. Because of the foregoing, according to the prior art, said control plate is mounted on the door through a spring plate so that it may be relatively movable between the door and the pack holder. And the control plate is moved in and out of the pack holder by utilizing the relative movements between the door and the pack holder which occur in opening and closing process of the door. When the door is in its locked state in the loading position, a pin planted in the apparatus body for positioning the control plate receives the control plate which is placed in the correct position by the action of a spring plate.
However, since the control plate is secured to the door in the afore-mentioned apparatus, relative movements between the door and the pack holder were indispensable in order to allow the control plate to move. Thus, the door and the holder could not be integrally constituted with respect to each other. In this way, when the door and the pack holder are separated, the door is required to be excessively rotated to open the insert gate of the pack holder. Accordingly, since the door is required to be opened widely, it is not preferable from a design view point. Moreover, since a gap is created between the door and the pack holder, there will be a possibility that the magnetic sheet pack is inserted therein by mistake. Furthermore, not only a pivotal mechanism of the door but also a pivotal mechanism of the pack holder are required, which adversely affects any serious attempts to make the apparatus compact or to reduce the number of component parts thereof. In addition, since the door and pack holder are required to be secured to the apparatus body separately, there is also an assembling disadvantage.
Furthermore, since an extremely high accuracy of repeatability of the correct positioning of the control plate with respect to the magnetic sheet and the magnetic head is required as mentioned above, if the control plate is to be secured to the door, even a slight external disorder with respect to the door adversely affects the contact opf the head against the magnetic sheet.